Its not a myth. I've done it because it originally came from a car in Japan. My friend had an EP82 with the rotary SAFC. He noticed that his car didn't seem to have a fuel cut. When we checked it out he had very big injectors, 440cc according to the part numbers. Then it all started to make sense once you knew how the SAFC worked. You will hit fuel cut at the voltage representation for it at the MAP sensor. The FC is still there, and always will be there with the SAFC, but the level at which you hit it will depend on the one factor of voltage.
That factor varies based on the size injectors you have. The bigger the injectors the lower the voltage the MAP sensor has to see to make them work properly because lower voltage means less fuel. This by extension means the AFR you're running will determine where the fuel cut is. The only way to know is that you have to watch the MAP sensor voltage to figure out where it is.
You can trigger the FC from 1000rpm if you increase the SAFC percentage high enough.
I've seen this method of FC 'removal' done on several local cars including my own. The problem with this method is that you a)first have to find out where the FC has been moved to which means turning up the boost until you active it or see the FC voltage b)its limited to the fueling and injectors size in the vehicle. Boost is boost, but injector duty cycle to match incoming air is dependent upon CFM, therefore 10psi on a CT9 might not trigger the FC, but 10psi on a T3 would c)since fueling is not linear the FC might get triggered by engine load and not engine speed making spikes and creep a potential danger depending on how close you are to the FC voltage.
So you understand there are two types of FCD.
http://hardcore.ep91.com/engine_fcd.html Resistor and clamp type. Resistors just move the voltage just like the SAFC. Its still there. Clamp types remove it completely because the ECU will never see a voltage higher than the clamp setting. With a resistor type FCD there is a voltage error across the whole fuel table that must be compensated for. On the clamp type the ECU will fuel on the last voltage received.